hw/display/ramfb.c

   1 /*
   2  * early boot framebuffer in guest ram
   3  * configured using fw_cfg
   4  *
   5  * Copyright Red Hat, Inc. 2017
   6  *
   7  * Author:
   8  *     Gerd Hoffmann <kraxel@redhat.com>
   9  *
  10  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  11  * See the COPYING file in the top-level directory.
  12  */
  13 #include "qemu/osdep.h"
  14 #include "qapi/error.h"
  15 #include "hw/loader.h"
  16 #include "hw/display/ramfb.h"
  17 #include "ui/console.h"
  18 #include "sysemu/sysemu.h"
  19
  20 struct QEMU_PACKED RAMFBCfg {
  21     uint64_t addr;
  22     uint32_t fourcc;
  23     uint32_t flags;
  24     uint32_t width;
  25     uint32_t height;
  26     uint32_t stride;
  27 };
  28
  29 struct RAMFBState {
  30     DisplaySurface *ds;
  31     uint32_t width, height;
  32     struct RAMFBCfg cfg;
  33 };
  34
  35 static void ramfb_fw_cfg_write(void *dev, off_t offset, size_t len)
  36 {
  37     RAMFBState *s = dev;
  38     void *framebuffer;
  39     uint32_t fourcc, format;
  40     hwaddr stride, addr, length;
  41
  42     s->width  = be32_to_cpu(s->cfg.width);
  43     s->height = be32_to_cpu(s->cfg.height);
  44     stride    = be32_to_cpu(s->cfg.stride);
  45     fourcc    = be32_to_cpu(s->cfg.fourcc);
  46     addr      = be64_to_cpu(s->cfg.addr);
  47     length    = stride * s->height;
  48     format    = qemu_drm_format_to_pixman(fourcc);
  49
  50     fprintf(stderr, "%s: %dx%d @ 0x%" PRIx64 "\n", __func__,
  51             s->width, s->height, addr);
  52     framebuffer = address_space_map(&address_space_memory,
  53                                     addr, &length, false,
  54                                     MEMTXATTRS_UNSPECIFIED);
  55     if (!framebuffer || length < stride * s->height) {
  56         s->width = 0;
  57         s->height = 0;
  58         return;
  59     }
  60     s->ds = qemu_create_displaysurface_from(s->width, s->height,
  61                                             format, stride, framebuffer);
  62 }
  63
  64 void ramfb_display_update(QemuConsole *con, RAMFBState *s)
  65 {
  66     if (!s->width || !s->height) {
  67         return;
  68     }
  69
  70     if (s->ds) {
  71         dpy_gfx_replace_surface(con, s->ds);
  72         s->ds = NULL;
  73     }
  74
  75     /* simple full screen update */
  76     dpy_gfx_update_full(con);
  77 }
  78
  79 RAMFBState *ramfb_setup(Error **errp)
  80 {
  81     FWCfgState *fw_cfg = fw_cfg_find();
  82     RAMFBState *s;
  83
  84     if (!fw_cfg || !fw_cfg->dma_enabled) {
  85         error_setg(errp, "ramfb device requires fw_cfg with DMA");
  86         return NULL;
  87     }
  88
  89     s = g_new0(RAMFBState, 1);
  90
  91     rom_add_vga("vgabios-ramfb.bin");
  92     fw_cfg_add_file_callback(fw_cfg, "etc/ramfb",
  93                              NULL, ramfb_fw_cfg_write, s,
  94                              &s->cfg, sizeof(s->cfg), false);
  95     return s;
  96 }